Refineries use crude oil as a feedstock and produce gasoline and other products. For quality control and other purposes, refineries take on-line samples of gasoline as it is blended. Refineries generally also take manual spot samples of gasoline for retention purposes using spot sampling systems. These manual spot samples are usually conducted in accordance with ASTM D 323-8 entitled “Standard Test Method for Vapor Pressure of Petroleum Products (Reid Method)”.
Gasoline blend manual spot sampling systems are produced by Dopak located in Holland and Houston, Tex. The Dopak Process Sampler Type S23 is used for manual spot sampling of gasoline for retention purposes. Manual spot sampling systems are also produced by Texas Sampling Systems (TSS) of Victoria, Tex. TSS produces a manual Continuous Sample Apparatus, model number TSS MD-Flow Thru Sampler for taking manual spot samples of gasoline for retention purposes. TSS owns the following patents for a manual spot sampling system: U.S. Pat. Nos. 5,301,560; 5,431,067 and 5,433,120. These three patents use a four-way valve to control flow, and a closed container which uses a septum-like stopper to collect the sample via a needle pierced through the septum. Importantly, in these three patents, the volume of sample is fixed based on the piping design. To change the amount of sample, the piping must be changed. There is a need for a better manual spot sampling apparatus to take retention samples of gasoline which do not require bottles with septum-like stoppers to receive the sample, and which allow the volume of the sample to be changed as desired without modifying the structure of the system.
TSS also owns U.S. Pat. No. 5,361,643 entitled LPG Sampling System which is not relevant to the present inquiry. A search located the following additional references: U.S. Pat. Nos. 4,440,032; 5,945,611; 4,077,263; 4,101,282; 4,651,574; 4,355,539; 4,532,813; 5,665,314 and 6,682,939.